DealBook Online

By AZAM AHMED, STEVEN M. DAVIDOFF and CHRIS V. NICHOLSON

Published: January 14, 2011

SPLITTING UP The Marathon Oil Corporation, led by Clarence P. Cazalot Jr., left, the president and chief executive, announced plans on Thursday to spin off its downstream business, creating two independent companies.

The first, which will keep the Marathon Oil Corporation name, will focus on exploration and production, while the second, the Marathon Petroleum Corporation, will deal with refining, marketing and pipeline transportation. When the deal is complete, Marathon Petroleum will be the fifth-largest refiner in the United States.

TIGER CUB Gil Caffray, a former chief trader at the hedge fund Tiger Management, will rejoin his old firm as chief investment officer.

The move could indicate that the founder of Tiger, Julian Robertson, may reopen his hedge fund to new investors after unwinding the firm nearly a decade ago. AZAM AHMED

ODDS AGAINST Tyler and Cameron Winklevoss are fighting to undo their legal settlement with Facebook and Mark Zuckerberg, the social network's co-founder. The parties reached their agreement in 2008, but it appears the Winklevoss twins have since had settlers' remorse.

It is not uncommon for litigants to try to renege on settlements once they are outside the pressures of a mediation, but the Deal Professor says this is a battle the Winklevosses will probably lose. STEVEN M. DAVIDOFF BUYOUT OFFER The board of Exco Resources, an oil and gas producer based in Dallas, said on Thursday that it was considering a buyout offer made by Douglas H. Miller, the company's chief executive, which values Exco at $4.35 billion.

Mr. Miller told the board in October that he was interested in buying the company. His offer of $20.50 for every share he did not already own was 38 percent above the share price before his bid was announced. CHRIS V. NICHOLSON